Exploring Individual and Sex Differences in Trace Eyeblink Conditioning (EBC) in 4- to 6- year-olds

Hannah Bowley1, , Yinbo Wu1, Priscilla Lioi1, Vanessa Vieites2, Yvonne Ralph3, Melanie Rengel1, Amanda Renfro1, Timothy Hayes1, Anthony Dick1, Aaron Mattfeld1, Shannon Pruden1


1 Florida International University
2 Rutgers University
3 University of Texas at Tyler

Introduction

  • Eyeblink Conditioning (EBC) is a form of Pavlovian conditioning that uses tone and air puff pairings to over time develop a learned association of the two stimuli within a subject.
  • Trace EBC is a novel technique used to gain a better understanding of hippocampal and cerebral-dependent learning that has been previously employed in both adults and animal subjects (Takehara, Kawahara, and Kirino 2003); (Cheng et al. 2008);(Vieites et al. 2020).
  • This study used Trace EBC to evaluate developmental changes in associative learning using the following metrics:
    • Conditioned Response (CR%) defined as the number of Eye Blinks occurring during trace period following the presentation of tone in paired trials and tone alone trials and prior to onset of unconditioned stimulus in paired trials - Accuracy
    • Onset Latency defined as onset time of blinks during paired and tone alone trials - Precision

Objectives

Aim-1: Examine individual differences in accuracy across blocks as measured through Conditioned Response Percentage (CR%)

Aim-2: Examine individual differences in precision across blocks as measured through changes in SD of Onset Latency

Methods

  • Participants: Sixty-seven typically developing 4- to 6- years old’s completed a trace EBC task.

  • Task: conditioned stimulus presentation (i.e., tone) followed by a 500-ms trace period of no stimulus presentation and a subsequent unconditioned stimulus (i.e., air puff to eye). Responses to stimuli (i.e., eye blinks) were measured. Stimuli presentation lasted approximately 15 minutes.

    • The EBC task consisted of 104 trials, one block of 4 practice trials to acclimate children to the stimuli and 10 blocks of test trials. Each test block consisted of 10 trials: 8- paired tone and air puff trials, 1- puff alone trial administered halfway through paired trials, and a final tone alone trial.

Analysis: Linear Mixed Effects models were implemented using lme4 package (Bates et al. 2023)

Results- Accuracy

No age related differences in accuracy on Trace EBC task as measured through Conditioned Response (%) across blocks

Type III AOV with Satterhwaite’s Method: CR (%) ~ Age * Block
Sum Sq Mean Sq DF F Value Pr(>F)
Block 2932.7 325.85 9 1.6538 0.09747
Child Age 66.5 66.48 1 0.3374 0.56350
Block X Child Age 3279.8 364.42 9 1.8495 0.05735

No sex related differences in accuracy on Trace EBC task as measured through Conditioned Response (%) across blocks

Type III AOV with Satterhwaite’s Method: CR (%) ~ Sex * Block
Sum Sq Mean Sq DF F Value Pr(>F)
Block 1354.60 150.511 9 0.7455 0.6671
Child Sex 12.23 12.235 1 0.0606 0.8064
Block X Child Sex 872.46 96.940 9 0.4802 0.8882

Results- Precision

No age related differences in precision on Trace EBC task as measured through Onset Latency (SD) across blocks

Type III AOV with Satterhwaite’s Method: Onset Latency ~ Age * Block
Sum Sq Mean Sq DF F Value Pr(>F)
Block 315785 35087 9 1.7857 0.06943
Child Age 2663 2663 1 0.1355 0.71425
Block X Child Age 298441 33160 9 1.6876 0.09025


No sex related differences in precision on Trace EBC task as measured through Onset Latency (SD) across blocks

Type III AOV with Satterhwaite’s Method: Onset Latency ~ Sex * Block
Sum Sq Mean Sq DF F Value Pr(>F)
Block 358550 39839 9 1.95750 0.04112*
Child Sex 146 146 1 0.0072 0.93259
Block X Child Sex 107262 11918 9 0.5908 0.80470

Discussion

  • The findings suggest no age or sex related differences in both precision and accuracy in a Trace Eyeblink Conditioning task as measured through conditioned responses (%) and blink onset latency.
  • As seen through Figure 1 and Figure 2, children in this age range were performing below chance in CR(%) suggesting that they were not learning the association across trial blocks.
  • The lack of changes in standard deviation across trial blocks indicates children were also not getting more precise with their blinks across trial blocks.
  • Future directions: Are there individual differences in Delay EBC compared to Trace EBC? At what age do children develop the association?

References

Bates, Douglas, Martin Maechler, Ben Bolker [aut, cre, Steven Walker, Rune Haubo Bojesen Christensen, Henrik Singmann, et al. 2023. “Lme4: Linear Mixed-Effects Models Using ’Eigen’ and S4.” https://CRAN.R-project.org/package=lme4.
Cheng, Dominic T., John F. Disterhoft, John M. Power, Deborah A. Ellis, and John E. Desmond. 2008. “Neural Substrates Underlying Human Delay and Trace Eyeblink Conditioning.” Proceedings of the National Academy of Sciences of the United States of America 105 (23): 8108–13. https://doi.org/10.1073/pnas.0800374105.
Takehara, Kaori, Shigenori Kawahara, and Yutaka Kirino. 2003. “Time-Dependent Reorganization of the Brain Components Underlying Memory Retention in Trace Eyeblink Conditioning.” The Journal of Neuroscience 23 (30): 9897–9905. https://doi.org/10.1523/JNEUROSCI.23-30-09897.2003.
Vieites, Vanessa, Shannon M. Pruden, Anna Shusterman, and Bethany C. Reeb-Sutherland. 2020. “Using Hippocampal-Dependent Eyeblink Conditioning to Predict Individual Differences in Spatial Reorientation Strategies in 3- to 6-Year-Olds.” Developmental Science 23 (1): e12867. https://doi.org/10.1111/desc.12867.

Acknowledgments

This work is supported by the NIH under Grant [R01HD098152]. For more information on this study please visit http://plsd.fiu.edu or contact Hannah Bowley at